EP2609049A1

EP2609049A1 - Phosphorescent compositions and use thereof

Info

Publication number: EP2609049A1
Application number: EP11754855.2A
Authority: EP
Inventors: Diana Friedrich
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-08-27
Filing date: 2011-08-29
Publication date: 2013-07-03
Anticipated expiration: 2031-08-29
Also published as: WO2012025634A1; EP2609049B1; PT2609049E; US20130153118A1

Abstract

The invention relates to a phosphorescent composition which contains lead-free glass powder and phosphorescence pigment. The composition is suited in particular for producing dyes, paints and glass items.

Description

Phosphorescent compositions and their use

The invention relates to phosphorescent compositions and paints and paints containing them. The invention further relates to articles made using these compositions, paints or lacquers, and to a process for producing afterglow glass articles.

Phosphorescent pigments, also referred to as persistence pigments, are insoluble in the application medium and have the property of being able to store incident light in the visible and, in particular, invisible range (UV range) and to release the stored energy time-delayed over a longer period of time in the form of visible light. Phosphorescent pigments can therefore be used to produce dark glowing inks and varnishes and so-called "glow-in-the-dark" articles, so that phosphorescent or luminescent materials can be used for information, security and decoration purposes on a wide variety of articles and surfaces be used, for example, as guidance markers for emergency exits and for the identification of steps.

However, in order to achieve a strong and lasting afterglow effect, one needs large quantities of these pigments, which makes the production of these products expensive because of the high cost of the pigments. The phosphorescent pigments must also be irradiated with light for an extended period of time to achieve the desired afterglow effect, and the duration of the persistence of the pigments is often short. Conventional luminescent paints and varnishes also tend to sediment and clump because of their high pigment content when applied to the substrate, and may exhibit an inhomogeneous and coarse-grained appearance. Furthermore, the paints and varnishes often adhere poorly to substrates such as glass, stone or textile. Thus, phosphorescent paints on floor coverings are worn away by wear or weathered over time. Photoluminescent adhesive materials or plastic strips, such as those used instead, for example, for marking on concrete, such as on stairs, easily detach because of the heavy stress and because of the poor adhesion to the porous substrate. DE-A-23 61 569 describes a signal and warning material, in the production of which a mixture of fluorescent, phosphorescent and reflective substances is used. In this context, this document also mentions reflective surfaces made of resins and crystalline substances or glass powder. The disadvantage of compositions containing glass powders and phosphors, however, is that, especially when in contact with moisture, there may be chemical reactions in which harmful gases such as hydrogen sulfide and sulfur dioxide may form and / or cause color changes or destruction the pigments and ultimately can lead to a complete loss of luminosity.

EP-A-0 182 744 describes photocurable epoxy resin compositions comprising an epoxy resin and a photoinitiator, which may further contain fillers, for example electrically and thermally conductive fillers, ferroelectrics and phosphorescent fillers, and fluxes, for example glass powder, flux only be used in the case of ceramic applications. As far as glass powder are used, however, these are only used together with electrically conductive or dielectric fillers. Examples containing phosphorescent fillers and glass powders are not described.

WO 2009/089920 describes phosphorescent concrete mixtures comprising photoluminescent luminescent pigments. The use of such produced concrete blocks, z. B. in the field of floor installation, but has the disadvantage that these stones are very expensive due to the amount of pigment material to be used because concrete is not translucent and thus only the uppermost cover layer of the stone lights. At least 50% of the pigment material used therefore remains without visible effect. The also described use of quartz powder as a transparency enhancer is also very expensive.

Object of the present invention is therefore to provide in the dark luminescent colors, paints and articles that have a good appearance and cost-effective wherein the pigments can be charged in a relatively short time and the colors and articles have a long burn time. Another object is to provide lacquers and paints, especially for spraying, which can be used both indoors and outdoors, on materials such as textile, metal, stone, glass, plastic, concrete, wood and asphalt adhere and easy to be applied.

This object has been achieved with the aid of the phosphorescent compositions of the present invention comprising: (a) glass powder, the glass powder being lead-free glass powder selected from soda-lime glasses, borosilicate glasses, float glasses and phosphate glasses; and

(b) Phosphorescent pigment. Glass powder of soda-lime glasses, borosilicate glasses, float glasses and phosphate glasses regularly have a certain lead content due to their production process and the additives used. It has now been found that compositions containing lead-free glass powder are more stable on storage and in contact with moisture are as compositions containing conventional lead-containing glasses. The compositions also make it possible to significantly reduce the amount of phosphorescent pigment used, without reducing the persistence of the products treated with the compositions according to the invention. At the same time, the duration over which the pigments must be exposed to light in order to store sufficient energy can be reduced. The compositions adhere well to substrates such as glass and fabric and exhibit good drying. The products also show a very homogeneous, fine-grained and bright appearance due to the presence of the glass powder.

Preferably, lead-free glass powders are used, which are also free of barium, arsenic and antimony, which are usually present in the starting materials used for glass production or used in glassmaking, for example in the form of barium oxide or antimony oxide, as a fining agent. Preferably, the iron content in the glass powder is 0.05 wt% or less, preferably 0.01 wt% or less, based on the mass of the glass powder. Glass powders free of the above-mentioned substances can be obtained by the usual glass-making method, taking care that glass production is carried out using raw materials free from the above-mentioned substances. Such glasses are known in the art. Lead and barium-free glass is described, for example, in WO 2005/090252.

By using lead-free glass powder of soda-lime glasses, borosilicate glasses, float glass and phosphate glass, the production costs can be further reduced. Particular preference is given to using soda-lime glasses and borosilicate glasses. Depending on the application, colored or colorless glass powders can be used. The concentration

3

the glass used is preferably in the range of 2.3 to 2.8 g / cm, especially

3 3

preferably in the range of 2.4 to 2.7 g / cm, for example at about 2.5 g / cm. The glass powder can be prepared by grinding the respective glass. Preferably, the glass powder has a particle size dl 00 of 500 μηι, i. 100% by weight of the glass powder particles may have a particle size of up to 500 μm and no particle greater than 500 μm. Preferably, the glass powder has a particle size dl 00 of 350 μη. As the glass powder, a single glass powder grade can be used or mixtures of two or more glass powder grades having different particle sizes or particle size distributions can be used. Due to the finer grain size distribution achieved by the addition of glass powder to the phosphorescent pigment and the lower density of the glass compared to the phosphorescent pigment, sedimentation of the pigment in paints or varnishes is slowed down and slowed down due to its high specific gravity Powder mixture remains in suspension for a longer time and does not clump so fast on the bottom of the application machine. Particle sizes and particle size distributions can be determined by sieve analysis according to standardized methods according to DIN 66165-1 and 66165-2.

The glass powder is preferably present in an amount of from 15 to 85% by weight, based on the total weight of glass powder and phosphorescent pigment in the composition. The amount of glass powder is preferably from 20 to 80% by weight, particularly preferably from 25 to 75% by weight.

As phosphorescent pigments it is preferred to use inorganic phosphorescent pigments, particularly preferably nonradioactive inorganic phosphorescent pigments. The phosphorescent pigment can consist of a single pigment, but preferably consists of mixtures of different pigments.

Particularly suitable phosphorescent pigments according to the invention are oxides of rare earths and sulfides, selenides, silicates, aluminates, fluoroaluminates, phosphates, halophosphates, borates, germanates, vanadates, molybdate and tungstates of preferably divalent metals such as Zn, Mn, the alkaline earth metals Be, Mg, Ca, Sr and Ba, and the rare earth metals, the pigments being used either as pure substance phosphors or doped with heavy metals such as Bi, Sn, Cu, Tl, Al, Mn, Pb and rare earth metals, in particular La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Tb, Ho, Er, Tm, Yb and Lu may be present. More preferably, the composition of the invention comprises at least one phosphorescent pigment selected from sulfides, aluminates and silicates doped with one or more heavy metals and / or rare earth metals. Examples of sulfides suitable according to the invention are ZnS, for example doped with Cu (ZnS: Cu), CaS: Bi and CaCdS: Cu. The aluminates useful in this invention include the alkaline earth aluminates, such as those described in US-A-5,424,006 and US-A-5,686,022. According to the invention are particularly suitable phosphorescent pigments, comprising a compound of the general formula MA1 ₂ 0 ₄ wherein M represents at least one element selected from Ca, Sr and Ba, or a compound of formula M _1-x AL20 _4- _x, wherein M has the above meaning or represents a combination of these elements with Mg, and x is in the range of -0.33 <x <0.60 (except x = 0). Such alkaline earth aluminates are doped with at least one rare earth metal, in particular europium (Eu) and / or dysprosium (Dy). Particular preference is given to Eu and / or Dy doped strontium aluminate (SrAl ₂ 0 ₄ : Eu, Dy). According to the invention suitable silicates are, for example, Zn ₂ Si0 ₄ and alkaline earth silicates. Particularly preferred is a Phosphoreszenzpigment comprising at least one pigment as described above based on a sulfide or aluminate or mixtures thereof. It has been found that compositions as Phosphorescent pigments containing or consisting of pigments based on an aluminate, in particular an alkaline earth aluminate, allow even longer stability and luminosity of the products produced with such compositions. Suitable phosphorescent pigments are commercially available, for example under the brand name Lumilux®.

According to a further embodiment, the phosphorescent pigment comprises at least one tungstate, wherein the phosphorescent pigment used is preferably a tungstate-containing pigment mixture. Examples of tungstates according to the invention are CaW0 ₄ and MgW0 ₄ , with MgW0 _{4 being} particularly preferred. Such a tungstate is usually used in an amount of 0.0001 wt .-% to 5 wt .-%, based on the total weight of the Phosphoreszenzpigments. It has been found that the brightness of the afterglow of the compositions according to the invention in the application medium can be further improved by a mixture of phosphorescent pigments which contain tungstates, in particular MgWO ₄ .

The phosphorescent pigment can be an unencapsulated or an encapsulated, ie an encased pigment or a mixture of uncapsulated and encapsulated pigment. Encapsulated pigments are known to the person skilled in the art. Encapsulated pigments which are suitable according to the invention are encased, for example, with glass, plastic or SiO ₂ . Such encapsulated pigments have higher heat and moisture resistance and are therefore particularly useful when the compositions are used under high temperature and / or humidity conditions. Encapsulated pigments also have increased UV resistance, are insoluble in organic solvents, and are resistant to acids and aqueous media. The proportion of encapsulated pigments in the total amount of the phosphorescent pigment is under these circumstances usually at least 5 wt .-%, preferably at least 10 wt .-%, particularly preferably at least 30 wt .-%, and may be up to 100 wt .-%. The phosphorescent pigment in the unencapsulated or encapsulated form preferably has a particle size d 1 00 of 500 μm, ie 100% by weight of the particles have a particle size of may have up to 500 μηι. Preferably, the Phosphoreszenzpigment has a particle size d100 of 350 μηι. The phosphorescent pigment may also be a mixture of pigments having different particle size distributions. The phosphorescent pigment preferably has at least one pigment fraction having a particle size d50 between 1 and 100 μm, preferably between 1 and 80 μm. On the one hand, mixtures of pigments having different average particle sizes lead to a more uniform luminous impression and, moreover, may prove particularly advantageous in order to avoid rapid sedimentation of the particles in an application medium, for example a binder for paints and varnishes. Particle sizes and particle size distributions can be determined in the usual way by sieve analysis in accordance with DIN 66165-1 and 66165-2, as in the case of the glass powder.

The phosphorescent pigment in the composition according to the invention is preferably present in an amount of 85-15 wt .-%, based on the total weight of glass powder and Phosphoreszenzpigment. Advantageously, the amount of phosphorescent pigment in the range of 80 to 20 wt .-%, particularly preferably from 75 to 25 wt .-%.

Preferably, at least one of the phosphorescent pigments contained in the composition has an afterglow intensity after 10 minutes, determined in accordance with DIN 67510,

2 2

of at least 3.0 mcd / m, preferably of at least 10 mcd / m, more preferably of at least 50 mcd / m.

The composition according to the invention furthermore preferably has at least one phosphorescent pigment whose emission wavelength _max (emission maximum) is in a wavelength range from 380 to 500 nm (violet to blue), a wavelength range from 510 to 580 (green) or a wavelength range from 590 to 750 nm (red ) lies. In the green or the blue region emitting phosphorescent, for example, Zn ₂ Si04: Mn, ZnS: Cu, SrAl ₂ 0 _4: Eu, BaAl ₂ 0 _4: Eu and CaA ^ C ^ Eu, an emitting in the violet range pigment is CaAl ₂ 0 ₄ : Eu, Nd, and a phosphorescent pigment emitting in the red region is, for example, CaS: Eu, Tm. Preference is given to using phosphorescent pigments in the violet, blue and green range. Preferably At least one of the phosphorescent pigments emitting in the violet, blue or green region has an afterglow intensity, determined in accordance with DIN 67510, of

2 2

at least 10 mcd / m, more preferably at least 50 mcd / m, after 10 min, and at least one of the phosphorescent pigments emitting in the red region preferably has an afterglow intensity of at least 3.0 mcd / m, more preferably from

2

at least 4.0 mcd / m, after 10 min. By mixing different phosphorescent pigments, different color effects can be achieved. For example, by mixing appropriately doped alkaline earth aluminates and silicates, for example those which emit in the blue, green and red regions, a white afterglow can also be achieved.

According to a further embodiment, the composition according to the invention also contains a fluorescent pigment (daylight pigment) in addition to the phosphorescent pigment. Fluorescent pigments are understood as meaning those pigments which emit only light as long as they are irradiated with light, in particular UV light, ie the light emission regularly ends within less than one thousandth of a second after the irradiation. Suitable fluorescent pigments are preferably inorganic fluorescent pigments such as oxysulfides of rare earth metals, in particular Eu-doped yttrium oxysulfide (Y20 ₂ S: Eu), as well as metal-doped sulfides such as ZnS. The proportion of the fluorescent pigment in the composition is preferably at least 10 parts by weight of fluorescent pigment per 100 parts by weight of the total mass of glass powder and phosphorescent pigment. The presence of such a fluorescent pigment also allows illumination of the article treated with the composition of the invention during the time that the phosphorescent pigment is being charged and storing energy. The luminous effect therefore also appears under illumination of the objects with UV-containing light, depending on the pigment and only at certain frequencies in appearance. Fluorescent pigments can have different colors in daylight. The daylight color and the occurring luminous color on irradiation with light of the activation frequency may be different or the same.

According to a further embodiment, the composition according to the invention can also effect powder, for example metal powder, in particular noble metal powder, such as Silver and gold powder, and magnetic powder containing, wherein the particle size dl 00 of the powder is preferably 500 μηι, more preferably 200 μηι. The presence of such a powder, in conjunction with the phosphorescence and fluorescence effects, results in a particular appearance of the articles treated with the compositions, for example metallic effects.

The compositions of the invention can be used to make paints and inks. For this purpose, the compositions, which may contain colored or colorless, preferably colorless, glass powder, are introduced into a binder customary for paints and coatings. Examples of suitable binders are natural resins and oils, lime, glue or preferably plastic-based binders, for example binders based on alkyd resins, acrylic and methacrylic resins, polyvinyl acetate copolymers, epoxy resins, polyurethanes and mixtures thereof. Optionally, the dye or coating compositions according to the invention comprise customary organic solvents, for example aliphatic, cycloaliphatic or aromatic hydrocarbons, such as hexane, cyclohexane and xylene, monohydric or polyhydric alcohols, such as propane, n-butane, isobutane and glycol, glycol ethers, such as butylglycol, butyldiglycol , Ethylene glycol and diethyl glycol, ketones such as acetone and methyl ethyl ketone, and esters such as butyl acetate, ethyl acetate and butyl glycol acetate, or are present as a dispersion in water. Optionally, the compositions contain other conventional additives such as cure accelerators and plasticizers. Preference is given to binders based on acrylic resins. The amounts in which the composition according to the invention is introduced into the binder correspond to the amounts customary in the case of paints and coatings for other pigments. The amounts to be introduced also depend on the desired effect and can be easily determined by the skilled person by simple experiments. Usually, the weight ratio of phosphorescent composition to binder is in the range from 1: 6 to 6: 1, preferably from 1: 4 to 4: 1.

The paints and varnishes according to the invention are outstandingly suitable for coating a wide variety of support materials, for example wood, natural and artificial stone, concrete and reinforced concrete, metals, plastics, textiles, paper, glass, ceramics, asphalt and enamels, to which they are customarily applied, for example by spraying, painting or dipping can be applied. Optionally, the support may first be provided with a conventional primer before the lacquers or paints of the invention are applied. Preference is given to using light primers, because then the light effect comes to its best advantage. The layer of the paints and varnishes according to the invention is customarily provided with a clearcoat which is advantageously at least partially UV-transparent, as a covering or protective layer, for example a polyurethane-based two-component clearcoat which protects the pigment layer from water and abrasion.

The compositions of the present invention are also eminently suitable for coating concrete surfaces, any type of concrete such as site concrete, ready mix concrete, shotcrete, underwater concrete, rolled concrete, spun concrete, vacuum concrete, construction concrete, screed concrete, aerated concrete, fiber concrete, mineral concrete, concrete concrete, self-compacting concrete , high-strength and ultra-high-strength concrete, glass foam concrete, exposed concrete, asphalt concrete, chippings, polymer concrete and paper concrete.

In the coating of concrete products can advantageously be used simultaneously phosphorescent and fluorescent or both pigments individually. As a result, the concrete product shines on UV irradiation and in the dark from dawn. An advantageous additional benefit is that the light required by the fluorescent effect simultaneously charges the phosphorescent pigments. An example of an application of concrete products made of coated light-weight concrete is the use as stair steps for marking stair-step edges. For this purpose, the concrete products can be produced, for example, with a pigment-glass composition according to the invention which contains a fluorescent pigment with the daylight color green and the UV light color red. The pigment mixture used is UV-stable and therefore suitable for outdoor use. The green daylight color ensures that the concrete step edges during the day act as a guide for the end of the step and are almost indistinguishable from conventional adhesive strips. When darkness sets in, the staircase lighting is switched on, but in addition to the standard lamps, UV lamps are also used or supplemented in the existing lamps. As soon as the UV lamps are switched on, the fluorescent concrete blocks glow in the red fluorescent color. When switching off the light effect is extinguished and the afterglow of the phosphorescent pigment remains. Thus, when fluorescent pigments are used, it may be possible to achieve a strong luminous effect through illumination by means of artificial or natural light sources during charging.

Exemplary uses for producing articles of coated concrete material are concrete pebbles of various sizes, shapes and colors; Concrete products for urban and road construction, gardening and landscaping in the form of surface systems, large format boards, eco-flaps, patio tiles; Gebäudeverplankungen; Prefabricated parts, in particular finished steps / stairs, roof concrete slabs, beams, pillars; Bricks, concrete furniture (e.g., benches, flower boxes, tables), swimming pool components (e.g., deckle curtains, launching blocks, jump equipment), balconies and balcony attachments, covers (e.g., manhole covers, outlet covers, bezel panel controls); Clinker; Enclosures (e.g., walls, pedestal walls); Surrounds of walls; partitions; Prefabricated components, in particular outer walls, curbs, dividing elements, supports; Roof structures and roof elements; Parts of and complete ramps, sidewalks and open spaces and traffic areas as well as their boundaries or complete markings; Parts of or whole obstacles including their markings; Slope stabilization stones (L-stones etc.); Grandstand safety devices, in particular markings of the safety-relevant escape routes or railings and / or other boundary boundaries; supporting and non-supporting walls; and boundaries incorporated into soils. Concrete pebbles, which are coated with the paints and colors according to the invention, moreover represent an environmentally friendly alternative to the commercially available "plastic stones".

The compositions according to the invention are also outstandingly suitable for the production of plastic, paper, stone, glass and ceramic articles, it being possible for the composition according to the invention to be incorporated in or applied to the starting materials. The compositions according to the invention are particularly suitable for the production of glass and ceramic articles, in particular glass articles such as glass rods, glass stones, glass beads and glass tiles, at least partially colored glass powder preferably being used as the glass powder. The glass powder of the composition according to the invention can in this case include both colorless and colored glass. For the production of glass articles, for example glass tiles, it is possible, for example, to proceed as described in DE-A-101 30 011. Usually, accordingly, a powder layer of the composition according to the invention is applied to a first glass section, preferably a gob of viscous glass, for example a glass blank of the desired size, whereupon a second glass section covering the layer with the phosphorescent pigment, preferably a gob also of viscous glass, for example a corresponding second glass blank, on the first glass portion, preferably the still viscous gobs, applied and fused thereto, including the layer with the Phosphoreszenzpigment. The presence of the glass powder in the composition according to the invention allows a particularly good adhesion between the respective glass sections.

The paints and inks according to the invention which contain the glass powder and the phosphorescent pigment can therefore be easily applied because of their stability and have excellent mechanical properties, such as abrasion resistance, compressive strength, impact resistance, scratch resistance, acid resistance and skid resistance. It allows the coating of any surface and offers a variety of uses, creating a cost-effective, low-maintenance and flexible way to easily provide long-lasting and durable markings and articles in a simple and uncomplicated way.

The present invention is further illustrated by the following non-limiting examples.

Examples

Comparative Example 100 g of a green-phosphorescent pigment (UV element, Nordhausen, Germany) having a particle size of 25-70 μm were mixed with 150 g of a commercial acrylic resin as binder. The varnish composition thus obtained was uniformly sprayed with a spray gun onto a cleaned, white emulsion paint primed and dried aluminum plate (25 x 10 cm). After drying the first layer, the injection process was repeated twice more, the individual layers were each dried well. It was then sealed with a commercially available two-component clearcoat with three layers.

The panel was exposed to daylight for 4 hours and then viewed in a dark room. A dark green glow was observed, which remained visible for about 3 hours.

example 1

In parallel to the above experiment, 30 g of the green phosphorescent pigment (UV element, Nordhausen, Germany) and 70 g of glass powder with a particle size dl 00 of 250 μιη in 150 g of the same acrylic resin binder were mixed. The varnish composition obtained in this way was again sprayed evenly with a spray gun onto a cleaned, white emulsion paint primed and dried aluminum plate (25 × 10 cm). After the first layer had dried, the injection process was repeated twice more, the individual layers each being dried well. Subsequently, it was sealed as above with a commercially available two-component clearcoat with three layers.

After 4 hours of exposure to light under the same conditions as above and observation in the dark room, a glow in bright neon green was observed over 1.5 hours was significantly lighter than the glow of the pigment without glass powder content. After this bright glow subsided, the standard illumination of the pigment came to light, which remained visible for 4 to 6 hours. At the same time, a brightening of the daytime hue was observed, changing from yellow to whitish yellow. The light was more uniform in fine-grained appearance than in the sample without glass powder.

The above experiments show that the presence of the glass powder leads to a brighter light than pigment without glass powder, and that the duration of the afterglow is prolonged overall. It can be assumed that this is due, on the one hand, to a reflection of the emitted radiation by the glass particles and, on the other hand, to a more rapid charging of the pigment in the presence of the glass particles. In addition, the presence of the glass particles leads to a lightening of the visible color during the day. Moreover, because of the different particle sizes of glass powder and pigment, the luminance appears more uniform and the pigments are more stable to disperse and the paint can be applied better.

Example 2 A mixture of white portland cement and quartz sand was produced to produce a large format concrete slab, and from this mixture a concrete was prepared which, after shaping, smoothing and, optionally, shot peening and coating with a first special lacquer layer to seal the concrete surface Low-pressure high-volume paint sprayer with a sprayed as described in Example 1, mixed with water paint composition was sprayed. Depending on the layer thickness and number of layers, the luminosity is varied. After drying this pigment glass layer, a protective lacquer is sprayed on, with several layers being applied in order to achieve the best possible protection. This gives a large format plate that lights up after being excited by the daylight at night. At night, recharge can be done by UV lighting to set the luminous intensity permanently high. The topcoat on the crystalline luminescent pigment glass layer on the concrete ensures a high abrasion resistance and for a lasting functioning of the plate. The plates thus obtained light up after sufficient exposure to sunlight or by artificial UV illumination in the dark for about 12 hours. However, the duration of illumination can be influenced by the choice of pigment and the proportion of the glass.

Example 3

Production of luminous concrete pebbles

From the concrete mix of Example 2, irregular pebbles were formed via a dripping process wherein the liquid concrete dripped through a metering orifice (drip ring) onto a conveyor belt (of various grades, adjustable to achieve different degrees of rounding). After the drying process, the pebbles were dropped onto a coarse mesh (just so large that the stones did not fall through) and allowed to travel through a bath of liquid light pigment glass composition used in Example 2. Depending on the mixing ratio of base medium, water and the luminous mixture used, different viscosities were produced which, in combination with the traveling speed of the conveyor belt, led to different coating thicknesses, which in turn influenced the luminous intensity. After the drying process, a bath is passed through with the topcoat, whereby here too the conveyor belt speed determines the thickness of the protective lacquer.

The plates thus obtained illuminated after sufficient exposure to sunlight or by artificial UV illumination in the dark for about 12 hours. The duration of illumination was influenced by the choice of pigment and the proportion of the glass.

Alternatively, the application of the pigment mixture and the topcoat can be done via a high-volume low pressure device, wherein the conveyor belt must be adjusted with shaking movements for rotation of the pebbles.

Claims

claims

A phosphorescent composition comprising:

(a) glass powder, wherein the glass powder is lead-free glass powder selected from soda-lime glasses, borosilicate glasses, float glasses and phosphate glasses; and

(b) Phosphorescent pigment.

A composition according to claim 1, wherein the glass powder is selected from soda-lime glasses and borosilicate glasses.

A composition according to claim 1 or 2, wherein the glass powder is present in an amount of 80-20% by weight and the phosphorescent pigment in an amount of 20-80% by weight, based on the total weight of glass powder and phosphorescent pigment.

Composition according to one of claims 1 to 3, wherein the glass powder has a particle size dl 00 of 500 μπι and the Phosphoreszenzpigment has a particle size dl 00 of 500 μηι.

A composition according to any one of claims 1 to 4, wherein the phosphorescent pigment comprises at least one phosphorescent pigment based on a sulfide, aluminate, silicate or mixtures thereof.

A composition according to any one of claims 1 to 5, wherein the phosphorescent pigment comprises at least one phosphorescent pigment whose emission wavelength X _{max is} in a wavelength range of 380 to 500 nm, a wavelength range of 510 to 580 nm or a wavelength range of 590 to 750 nm. A composition according to any one of claims 1 to 6, wherein the phosphorescent pigment comprises at least one encapsulated phosphorescent pigment.

A composition according to claim 7, wherein the phosphorescent pigment is encapsulated with glass, plastic and / or Si0 ₂ .

A composition according to any one of claims 7 and 8, wherein the encapsulated pigment is present in an amount of at least 5% by weight, based on the total weight of the phosphorescent pigment.

A composition according to any one of claims 1 to 9, wherein the composition comprises a tungstate.

A composition according to any one of claims 1 to 10, wherein the composition further comprises a fluorescent pigment.

A composition according to claim 1 1, wherein the fluorescent pigment is present in an amount of at least 10 parts by weight per 100 parts by weight total mass of glass powder and phosphorescent pigment.

A composition according to any one of claims 1 to 12, wherein the composition further comprises an effect powder.

A paint or varnish composition comprising a binder and a phosphorescent composition according to any one of claims 1 to 13.

A paint or varnish composition according to claim 14 wherein the binder is a plastic based binder.

16. A paint or varnish composition according to claim 14 or 15, wherein the binder is selected from binders based on alkyd resins, acrylic and Methacrylate resins, polyvinyl acetate copolymers, epoxy resins, polyurethanes, and mixtures thereof.

17. Use of a composition according to any one of claims 1 to 16 for the production of luminescent articles.

18. Use according to claim 17, wherein the article is a glass article, in particular a glass rod, a glass brick, a glass ball or a glass tile.

19. Use of a dye or lacquer composition according to any one of claims 14 to 16 for the coating of stone and concrete products.

20. A method for producing a luminescent glass article, wherein a phosphorescent composition is applied to a first glass section, after which a second glass section covering the luminescent pigment layer is applied to the first glass section, which is fused to the first glass section including the phosphorescent composition, characterized in that a composition according to one of claims 1 to 13 is used as the phosphorescent composition.

21. A method according to claim 20, wherein the first glass portion is a viscous glass article to which the phosphorescent composition is applied and, in the still viscous state, is over-struck with a glass gob forming the second glass portion.

22. The method according to any one of claims 20 or 21, wherein the glass article is a glass rod, a glass brick, a glass ball or a glass tile.

A phosphorescent article containing a composition according to any one of claims 1 to 13 or prepared using it or using a dye or lacquer composition according to any one of claims 14 to 16.